The storm looked likely to make landfall on the coast of North and SC but heavy rain was also expected in Virginia to the north and Georgia to the south.
At 11am local time on Wednesday (early Thursday AEST), the storm was located about 785km southeast of Wilmington, North Carolina.
Hurricane Florence is blasting toward the Carolinas, carrying sustained winds of up to 130 miles per hour and the threat of "life-threatening storm surge and rainfall", the National Hurricane Center says.
All eyes are on Hurricane Florence as it barrels towards the Carolinas.
While some of the computer forecasting models conflicted, the latest projections more or less showed the storm shifting southward and westward in a way that suddenly put more of SC in danger and imperiled Georgia, too.
North Carolina Governor Roy Cooper said, 'The time to prepare is nearly over.
He said there was "well over $US20 billion" in FEMA's disaster relief fund.
The National Hurricane Center's best guess was that Florence would blow ashore as early as Friday afternoon around the North Carolina-South Carolina line, then push its rainy way westward with a potential for catastrophic inland flooding. Sound unlikely? It's the same model that accurately predicted that last year's Hurricane Harvey, which also stalled over land, would drop 60 inches.
The threat of flooding extends next week to parts of Georgia, Maryland, Ohio, Pennsylvania, Tennessee, West Virginia, forecaster have said.
Georgia Governor Nathan Deal, concerned the storm would bring its devastation south, issued an emergency declaration for all 159 counties in his state.
"Due to impacts from Hurricane Florence, an evacuation order has been issued for coastal SC, including Charleston, Dorchester, and Berkeley counties, beginning at noon Tuesday, Sept. 11", a spokesperson for Boeing said by email.
Emergency preparations included activating more than 2,700 National Guard troops, stockpiling food, setting up shelters, switching traffic patterns so major roads led away from shore, and securing 16 nuclear power reactors in the Carolinas and Virginia.
The landfall location is expected to be between Wilmington and Morehead City, North Carolina. All seven of North Carolina's ferry routes were shut down. Recovery could take weeks or months.
"Even if you've ridden out storms before, this one is different". "It's going to happen". Till now as many as 1.7 million people have evacuated the region.
"Get out of its way, don't play games with it, it's a big one, maybe as big as they've seen", Trump said. Some reactors are undergoing prestorm checks now, and their reactors will be shut down 12 hours before the hurricane arrives, Green said. "But no matter how bad it's going to be, it will pass and our job will be to rebuild this community together".